Method of lubricating high temperature equipment for cooking food



Q Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE EDWIN J. BOHNEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO STANDARD OIL COMPANY, OF WRITING, INDIANA, A CORPORATION OF INDIANA METHOD OF LUBRICATING HIGH TEMPERATURE EQUIPMENT FOR COOKING FOOD No Drawing.

This invention relates to a method of lubricating high temperature equipment for cooking food, an example of such equipment being acontinuous baking oven.

Gontinuousbaking ovens are designed for baking bread in passage through the oven, the bread being placed upon trays and the trays being carried through on a continuous chain belt. For lubricating the chainbelt, it

is important to employ a lubricant having goodepenetration, which will not form obj ectionable odors when exposed to the high temperatures of the oven and which will provide effective lubrication under these severe conditions.

I have found that a satisfactory lubricant can be produced by suspending graphite in a highly refined light oil.' The graphite, when deposited upon the bearings, is able to withstand the high temperatures of the baking oven and properly lubricates the moving parts of the belt. It is carried readily to all the bearing surfaces by the light oil in which it is suspended, and the light oil vaporizes before temperatures are reached in which it might be decomposed. The objectionable fumes and odors, which are formed by the decomposition of ordinary graphite greases and oils, when such high boiling oils are employed under conditions of high temperature, are thus avoided.

In practice, it has been found extremely difiicult to keep the lubricant from coming in contact with the bread during the handling of the material, both before and after application to the chains. The highly treated light oil, which I employ to carry the graphite in suspension, is substantially odorless and does not contaminate the bread if brought in contact therewith. This oil is preferably made from straight run refined oil by treating with 93% sulfuric acid. Pref erably, I employ an oil having a boiling point of about 350 F. and an end point of about 575 F., although oils having a lower boiling point and a higher end point have been satisfactorily used. For example, if desired, treated light oils, having an end point as high as 700 F., may be satisfactorily used. A refined oil of the type described is per treatment.

Application filed September 16, 1929. Serial No. 393,110.

found to have lost its characteristic kerosene or other hydrocarbon odor after having been treated with 8 pounds of acid per barrel of oil. If desired, the oil may be treated in successive batches with varying amounts of acid found satisfactory to make four successive treats with 2 pounds of acid per barrel in each treat. The finished oil is substantially odorless, most of the objectionable constituents having been treated out by the acid.

:In preparing the lubricant, graphite in a very finely divided form is employed; for example, graphite sufficiently finely ground to enable it to remain in suspension in the oil for five minutes or more. I have satisfactorily used a fine form of graphite, known For example, it has been' graphite greases and oils, remained in sus pension for only about 10 seconds.

In practice, it has been found that the tration, and is well adapted for carrying graphite in suspension.

Although the present invention has been described in connection with the details of a specific example thereof, it must be understood that it is not intended that such details shall be limitative of the scope of the invention, except insofar as included in the accompanying claim.

I claim:

The method of lubricating high temperature equipment for cooking food which comprises applying thereto at low temperatures a suspension of graphite in a treated, tasteless, non-odorous, light hydrocarbon oil The highly refined ewgem whereby the oil penetrates and carries the graphite into remote portions of said equipment, and vaporizing said oil in situ, leaving the graphite in said remote parts of the equipment to serve as a lubricant, the vaporized oil being ungbjectionable because it is tasteless and non-odorous.

EDWIN J. BOHNEN. 

